Process for protecting a substrate with an arylsulfonamidopyrazine intumescent agent

ABSTRACT

Intumescent compositions of the invention comprise certain arylsulfonamidopyrazines, such as 2-sulfanilamidopyrazine, 2sulfanilamidobenzopyrazine, and derivatives thereof. The intumescent agents may be employed in conjuction with additives conventionally used in intumescent compositions. For use in protecting substrates from heat and fire, the intumescent compositions may be applied to the substrates in any suitable manner, such as by electrodeposition, spraying onto an adhesive substrate, or application of a coating composition comprising the intumescent agent.

m 3976?;Y3 @Jited Sfat' Roth [ PROCESS FOR PROTECTING A SUBSTRATE WITH AN ARYLSULFONAMIDOPYRAZINE INTUMESCENT AGENT [75] Inventor: Shirley H. Roth, Highland Park, NJ.

[73] Assignee: Cities Service Company, New York,

[22] Filed: Feb. 11, 1972 [21] Appl. No.: 225,661

[52] 11.8. C1. 117/136, 106/15 FP [51] Int. Cl. C09d 5/18, C09k 3/28 [58] Field of Search 117/136; 252/8.1; 106/15 FP [56] References Cited UNITED STATES PATENTS 3,535,130 10/1970 Webb l17/136 X 3,663,464 5/1972 Sawko.... 117/136 X 3,707,554 12/1972 Hardy 117/136 X Oct. 30, 1973 OTHER PUBLICATIONS Northey, Sulfonamides, pps. 31, 32, 79, (1948).

Primary ExaminerWilliam D. Martin Assistant Examiner-Harry J. Gwinnell Attorney-Richard S. Strickler et al.

[57] ABSTRACT 5 Claims, No Drawings PROCESS FOR PROTECTING A SUBSTRATE WITH AN ARYLSULFONAMIDOPYRAZINE INTUMESCENT. AGENT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to intumescent compositions and more particularly relates to such compositions containing a one-component intumescent agent.

2. Description of the Prior Art It is known that a substrate maybe protected from heat and fire by the application .of an intumescent composition. intumescent compositions of the prior art usually contain an intumescent agent havingat least three components; i.e., a carbonific, a spumific, and a catalyst; and they are typically characterized by the disadvantages of high cost, low spreading rate, relatively poor efficiency, poor water resistance, and poor weatherability.

As disclosed in US. Pat. No. 3,535,130, it has already been discovered that a one-component intumescent agent has advantages over multicomponent intumescent agents. However, the'intumescent agents of the patent have poor adherence to substrates and have an undesirable degree of moisture sensitivity.

SUMMARY OF THE INVENTION An object of this invention is'to provide a novel class of one-component intumescent agents.

Another object is to provide such-intumescent agents having good efficiency and a low level of moisture sensitivity.

These and other objects are attained by using as intumescent agents compounds corresponding to the formula:

wherein Ar is a divalent aromatic residue, R is hydrogen, hydrocarbon, halohydrocarbon, or acyl, andR" is a pyrazyl or substituted pyrazylradical.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The intumescent agentsof the invention may be any compounds corresponding tothe above formula. However, they are preferably compounds wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or'nitro derivative thereof. When the aromatic ringbears organic substituents, it is usually preferred that they be chloro or bromo. It is also preferred that the aromatic ring have at least one free reactive position.

As indicated'above, R of the formula may be hydrogen or a hydrocarbon, halohydrocarbon, or acyl radical, e.g., an alkyl, chloroalkyl, or bromoalkyl radical containing one to five carbon atoms, atphenyl, chlorophenyl, or bromophenyl radical, or an aliphatic or aromatic acyl radical.

R" is preferably a pyrazyl radical, but it may bear one or more substituents if desired. The substituted pyrazyl radicals most commonly found in these compounds are the chloro, bromo, carboxy, hydroxy,

amino, thio, sulfonamido, C,C alkyl, C C alkoxy, phenyl, and benzo derivatives, but compounds containing other substituted pyrazyl radicals are also utilizable. When R" is a substituted pyrazyl radical, the nitrogen of the sulfonamide group may be attached directly to the pyrazyl ring, or it may be attached to the pyrazyl ring through the substituent.

Exemplary of the intumescent agents of the invention are Z-sulfanilamidopyrazine, 2-(4-amino-3-chlorobenzenesulfonamido)pyrazine, 2-(3-amino-4-bromobenzenesulfonamido)pyrazine, 2-(4-amino-2-ethylbenzenesulfonamido)pyrazine, 2-(3-amino-4- chloromethylbenzenesulfonamido)pyrazine, 2-( 4- amino-Z-butoxybenzenesulfonamido)pyrazine, 2-(4- amino-3-chloromethoxybenzenesulfonamido)pyrazine, 2-(4-amino-3-carboxybenzenesulfonamido)pyrazine, 2-(3,4-diaminobenzensulfonamido)pyrazine, 2-(4- amino-2-acetamidobenzenesulfonamido)pyrazine, 2- (2-amino-4-nitrobenzenesulfonamido)pyrazine, 2-(4- methylaminobenzenesulfonamido)pyrazine, 2-(4- chloroethylaminobenzenesulfonamido)pyrazine, 2-(4- bromoethylaminobenzenesulfonamido)pyrazine, 2-(4- phenylaminobenzenesulfonamido)pyrazine, 2-[4-(pchlorophenylamino)benzenesulfonamido]pyrazine, 2- [4-(p-bromophenylamino)benzenesulfonamidolpyrazine, 2-(p-acetamidobenzenesulfonamido)pyrazine, 2- (p-benzamidobenzenesulfonamido)pyrazine, 3-chlor0- 2-sulfanilamidopyrazine, 3-bromo-2- sulfanilamidopyrazine, 3-ethylcarboxy-2- sulfanilamidopyrazine, 3-hydroxy-2- sulfanilamidopyrazine, 2-sulfanilamidoaminopyrazine, 3-amino-2-sulfanilamidopyrazine, 3-ethylthio-2- sulfanilamidopyrazine, 3-(4-aminophenylsulfonamido)2-sulfanilamidopyrazine, 3-methyl-2- sulfanilamidopyrazine, 3-methoxy-2- sulfanilamidopyrazine, 3-phenyl-2- sulfanilamidopyrazine, 2-sulfanilamidobenzopyrazine, 3-hydroxy-2-sulfanilamidobenzopyrazine, 3-carboxy-2- sulfanilamidobenzopyrazine, the corresponding naphthalene compounds, etc. When not readily available, these compounds may be prepared by known techniques.

For use in protecting a substrate from heat and fire, the intumescent agents of the invention may be applied in any suitable manner, e.g., electrodeposition, spraying of powdered intumescent agent onto an adhesive substrate, etc. However, it is usually preferred to compound the intumescent agent with a binder, e.g., nitrocellulose, and optionally also with one or more of the other ingredients conventionally used in intumescent compositions, e.g., stabilizers, dispersing agents, pigments, driers, biocides, anti-foamers, thickeners, protective colloids, fillers, blowing agents, etc.; disperse the composition in a suitable liquid medium, e.g., water or a solvent or solvent mixture; and apply the coating composition thus formed to the substrate to be protected. As is the case with conventional intumescent coating compositions, it is frequently convenient to apply these coating compositions in the form of a paint having a solids content of about 10-70 percent by weight and an intumescent agent/binder weight ratio of about 0.075-14/1 to deposit a coating having a dry thickness of about 0.0010.75 inch.

The intumescent agents of the invention are efficient, have low moisture sensitivity, and intumesce to form foams having good volume, cell structure, and adherence to substrates, such as wood, metal, and plastics.

They are also useful as flame retardants in normally flammable compositions.

The following example is given to illustrate the invention and is not intended as a limitation thereof.

EXAMPLE 1 Place 1 gram of 2-sulfanilamidopyrazine in an aluminum pan and flame it with a propane torch. The compound intumesces to form an excellent volume of foam having a good cell structure.

Similar results are also observed when 2- sulfanilamidobenzopyrazine and the other intumescent agents mentioned in the specification are substituted for the intumescent agents of the example.

It is obvious that many variations may be made in the products and processes set forth above without departing from the spirit and scope of this invention.

What is claimed is:

l. A process for protecting a substrate from heat and fire which comprises applying thereto an intumescent composition comprising as the intumescent agent a compound corresponding to the formula:

agent is 2-sulfanilamidobenzopyrazine.

3 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3.769.073 Dated October 30, 1973 Inventor(s) Shir] y H, h

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Co1umn 1 1ine 38, the portion of the formula reading "NHR' should read NHR" Co1umn 4, line 5, the portion of the formula reading "NHR" should read NHR Signed and sealed this 2nd day of April 19714..

(SEAL) Attest EDWARD M.FLETCHER, JR. C MARSHALL DANN Atte sting Officer Commissioner of Patent 3 

2. The process of claim 1 wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof.
 3. The process of claim 1, wherein R'''' is a pyrazyl radical or an alkoxy or benzo derivative thereof.
 4. The process of claim 1, wherein the intumescent agent is 2-sulfanilamidopyrazine.
 5. The process of claim 1, wherein the intumescent agent is 2-sulfanilamidobenzopyrazine. 